Category — Lukes Hope

When we talk about cave diving, we usually refer to diving upstream or downstream. Upstream and downstream refer to the commonly accepted direction of the flow of the fresh water in the cave system. Here in Mexico, that direction is from inland to the sea traveling perpendicular to the coast. That knowledge is so ingrained locally that the government includes it in its planning documentation. If you take a look at the image (Click it.) of the slide, you will notice red arrows pointing to the coast. The arrows represent the government’s official position on the flow of water around/under Tulum. It is also important to note that there are two versions of the urban planning documents issued by the local government. One issued in 2005 and one in 2007. If you look closely at the 2007 map you will notice the government has included stick maps of the local cave systems. This is a promising sign, the government is starting to incorporate cave survey data.

The problem is there is no empirical evidence to support the current common belief. There is anecdotal evidence that would support those hypothesizes, however it seems it may be incorrect.

On Friday night, Allie and I had the opportunity to go to Akumal and watch a handful of presentations given at the Centro Ecologico Akumal. There were a number of very interesting presentations, including: one on the dry caves of the area, one on the benefits of GIS, the formation of the local caves and one on the movement of water at Car Wash.

The talk about Yucatan cave hydrology and geochemistry was given by Patricia Beddows, a Research Fellow at McMaster University in Hamilton, ON, Canada. Patricia has been traveling to Mexico to study the caves for at least 10 years. Last year she and a team of volunteers performed a dye tracing experiment at Car Wash to determine the flow of the fresh water there. I believe the results are remarkable.

Before I go any further, she has so far performed one dye trace at this particular site Car Wash. Therefore, the results she shared can only be representative of the water flow conditions in the cave at that time. She mentioned that repeat dye tracing may show somewhat different results.

The experiment consisted of deploying two markers. She deployed one dye in the Cell Block section and at Cenote Luke’s Hope (Cenote Zacil Ha). Both sections are upstream or inland. The expected result was that both dyes would be detected at Cenote Carwash. However, what actually happened was quite startling. The dye that was deployed in the Cell Block section, just stayed there. It never really passed the restriction heading downstream towards the coast. So it would seem that at the time of the experiment, the water was not flowing from upstream to downstream as we all believe it does.

The dye that was released at Luke’s Hope also did something remarkable. It moved relatively quickly down to Cenote Carwash, this was expected. It also moved into the Room of Tears section, this was not expected.

It seems that the fresh water is not moving from upstream to downstream at Carwash. The new hypothesis is the water is entering the system from a perpendicular path from the North and then moving down stream and out of the system south. It is also blowing water into the Room of Tears section.

This is import for a couple of reasons. The first is resource planning. If the government assumes the water is moving from inland to the sea in a straight line, they will plan things like dumps and well fields accordingly. However, if the reality is the water is moving unpredictably; then there is a chance those plans will create a public hazard, such as contaminated drinking water.

The second reason it is import is, it means you and I are using the wrong terminology. There was some discussion at dinner about changing from talking about upstream and downstream to inland and coastal sides of the system. We wouldn’t want to be inaccurate when briefing our dives, right! You know how important it is to be accurate in your briefings, don’t you? So get out of the nineties and your halogen lights and into modern times, it will be Costal and Inland from now on.

Lastly, the term upstream gives the impression that the flow will be working with you to assist you in exiting. When in reality, it may be working against you as the finding suggests. For example, when exiting Room of Tears. I bet you never considered that the Room of Tears might be a siphon. A very weak siphon, but a siphon. I can think of at least one place in Nohoch where there is a strong current against you when exiting, where common knowledge would indicate there shouldn’t be water moving against you.

Naturally, you should now ask, “Why isn’t the fresh water moving the direction of the cave?” The answer is equally interesting. In the last million and a half years or so, the sea level has dropped substantially from today’s levels at least 3 times. It was during one of these low periods that the cave system was formed. No one is really sure during which low period the caves formed. Therefore, the caves were formed during a period that had significantly different geomorphic forces at work then are at work today. When the cave was formed, the water did move in the direction of the cave. It was the eroding force that formed the cave.

Today, sea levels are much higher and the caves are full of water. The movement of water beneath the ground on the Yucatan is controlled by: the tides, the macro geologic formations and hydrostatic pressure from inland. (I consider the local caves micro when compared the to entire Yucatan.) The caves we dive are just happy accidents from the ancient past that provide us with hours of enjoyment. It is my unscientific opinion that Patricia’s findings suggest the following, “where the fresh water does flow in the direction of the cave, it is a coincidence”. It is my belief that the Yucatan is too porous and large for the relatively small cave passages to have meaningful effect on the macro movement of the water.

Patricia’s presentation was a call for further research. Every year, as more caves are mapped and more research is completed, we learn more about our favorite dive sites. Sometimes new information turns our commonly accepted knowledge on its ear and forces us to consider that our world is ever more complicated and beautiful then we expect.

On Friday morning our friend Paul flew into town to do some cave diving! It was his first trip after finishing full cave with Protech in November. We planned to do 2 dives a day Friday through Monday. However, the airlines had other plans and his flight was late on Friday, so we were limited to a warm up dive on Friday. First thing we did was to go over to Chac Mool and do a quick gear review. Paul had just gotten a beautiful new Halcyon harness and donut wing. We revised his hose routing a little and tweaked some other minor things. Those minor improvements really made a difference.

The crew was Allie, Paul and myself. Paul and Allie were in backmount and I was in side mount. We got in the water, did our S drill and dropped down. The dive was called immediately on account of Allie not being able to equalize. Unfortunately, she had been suffering a minor cold. There were tears all around and then Paul and I elected to continue the dive. We did a quick S drill and started the dive. Paul did a nice job of running the reel. We made the 30 minute swim down to The Monster. The Monster is the world’s largest underwater stalagetite. It measures 45feet tall and it hangs into a pit that is 90feet deep. It is really stunning the first time you see it. I always want to swim over to it and put my arms around it. We chose to dive Chac Mool becuase it is a realatively easy dive and there is only one T to contend with and that leads to a air doom that is breathable. Most of this dive is pretty ho hum, as you get to The Monster the rooms become more decorated and enjoyable. The return trip was uneventful. When we got back to Playa we decided to go to one of our favorite restaurants, La Cueva Del Chango.

Saturday brought fabulous weather and we headed down to Tulum for some diving. Allie wanted to give her head another day to clear, so Paul and I were on our own. We decided to go to Grand Cenote and do two dives. The first dive was down to the Cuzan Ha Loop. We elected to make this dive a little more complex, so we took the short cut jumping to the left on the first arrow. At the end of the line we jumped back onto the main line and turned left. We gapped at Cenote Ho Tul. The dive was going fantastic. We were making good time and I could tell Paul was in complete sensory overload. When we got to to the jump for the circuit a little miscommunication/confusion occurred. I went to set the spool to close the loop and Paul followed me. When I realized he was behind me, I sent him back and then finished up. We I returned to the main line, we continued the dive. We made it about 3/4 of the way around the circuit and had to turn on thirds. As we exited we cleaned up our gear and took our time. This is a beautiful dive and it is fun. The restriction after Cenote Ho Tul is good fun and I particularly enjoy it.

The second dive was towards Lithium Sunset. Last time I tried to find the jump off the mainline, I just couldn’t figure out where it was. I guess I wasn’t persistent enough. The picture I had in my mind’s eye was short jump, the reality was it is about 50 feet or so. Maybe less if you make it a straight shot. So we made the jump, went to the second arrow and made the short jump to the left. This is another beautiful dive although it is a little less challenging. If there is a no brainer, this is one of them. Just set the cruise control and enjoy the scenery. Some dives are just easier/less engaging then others. Paul was over joyed at the end of the dive. I was super relaxed and really enjoyed the dive. Grand Cenote is really a wonderful place to dive. The cave is bright white almost blue-ish and is highly decorated.

Sunday Allie decided to join us. We planned to go down past Tulum to Cenote Cristal aka Naharon. I wanted to give Paul the experience of the caves north of Tulum, in Tulum and south of Tulum. My experience is that they offer very distinct dives. And let me tell you, Naharon is no slouch! Naharon is feed by swampy lands to the north and west. Therefore the water in the system is tanic and stains everything. Naharon is about the darkest place I have ever dived and Allie and I find it to be a very psychologically challenging. It literally eats HID light. The darkness makes it very tight and unforgiving. This challenge makes the dive some much more rewarding! Once your field of view starts to open up, you discover the the black silk floors and the black stained formations are amazing. It is really like diving into the belly of a beast. On the main line there is a portal in the rock that looks like the jaws of a shark. As I pass through the formation, I imagine being swallowed by the beast. I guess the Halocline room is the belly.

Naharon is a little deeper then most of the other caves we dive. We plan for a depth of about 70feet and to stay out of deco we use 32% EAN. The plan was to head up to the Halocline Room; which is about a 25 minute swim up the main line. The most striking feature of the Halocline Room is the demarcation on the walls between the fresh water and salter water. The wall below the saltwater is perfectly white. The wall above is tanic stained black. My understanding is that the saltwater eats the black stain. It is really stunning and a worthwhile dive. I really want to get down to Naharon with my CCR or a couple of stages. I can only imagine what treasures hide in the inky blackness.

Dive over, it was time for food! We headed into Tulum for some Chicken! I love the chicken in Tulum. Our favorite place to eat is Pollo Bronco. It is an orange building on a corner on the north bound side of the road. Chicken can be had in the following sizes: quarter, half and whole. There are not really any other options. I think you can get pasta instead of rice. But, I never do.

Lunch over, it was time for diving. We drove over to Car Wash for a little dive. Car Wash is a cenote where the taxi drivers used to wash their cars. The land owner has really made some improvements to this site since that time. There are rest rooms, changing rooms and tables to setup on. They have built a reception area at the Luke’s Hope cenote. It is really nice.

This time of year there is a cloudy layer for the first 10 feet in the cenote then visibility opens up. It is really awesome to drop down through the cloud into clear water and to watch a friend do the same. The visibility reminds me of wreck diving in NJ.

This time it was Paul’s job to run the primary. We setup our primary tie in on a tree a couple of feet from another team’s, then we proceeded in. What we found was an unbelievable spider web of line. The team ahead of us had literally criss crossed the cave at different depths at least three times. Paul was confused and I was livid! Message to all you Muppets out there, “CAVE DOESN’T BELONG TO YOU!” There are other teams in the world, have some common decency. We spent an unreasonable amount of time negotiating the other team’s line. In the end we had two choices: call the dive or install our gear woven through theirs. We choose to install our gear. I helped Paul to take the most respectful path possible. Then we hit another snag, Paul’s primary reel was too short. I loaned him a spare Spool and we gapped to the main line. The lesson here is; confirm how much line you have on your primary reel. Don’t take the manufactures word for it. Unfortunately, the cavern debacle cut our penetration short. I think we made it 15 minutes past Luke’s Hope and Paul turned us on thirds.

When we got back to open water, we recalculated thirds and went for a little exploratory dive down stream. Again we ran into the other team. Again they had taken the entire cave to themselves with their handy reel work. What a headache. Please learn to use your reel!

Monday was going to be a short day for Paul and I. Since he hadn’t been to Minotauro, we went over and did the circuit in two dives. I blundered in my briefing, but nothing severe enough to call the dive. I actually realized it as soon as we submerged on the first dive. We setup the circiut and returned. The second dive we completed the circuit. The only thing notable was that I did the in about 1000PSI. I guess all this working out and concentrating on finning technique is paying off.

Paul’s trip was fantastic and we had a great time. Hopefully he will come back soon and we can do some more diving. There are just too many beautiful places to see!